Camshaft construction



Nov. 14-, 1967 R. E. HULTEN 3,352,293

CAMS HAFT CONSTRUCTION Filed July 28, 1965 2 Sheets-Sheet l fix I I I 10e fiiyj zMM ATTORNEY Nov. 14, 1967 R. E. HULTEN 3,352,293

CAMSHAFT CONSTRUCTION Filed July 28, 1965 2 Sheets-Sheet 2 f/ga I NVEN'TOR.

& 52221020 6. #1111222 E if ATTORNEY United States Patent Delaware FiledItaly 28, 1965, Ser. No. 475,405 4 Claims. (Cl. 123-90) ABSTRACT OF THEDISCLOSURE An internal combustion engine includes overhead valvesactuated by rocker arms pivoted on hydraulic lash adjusters. An overheadcamshaft actuatingly engages the- This invention relates to internalcombustion engines and more particularly to the construction of thecamshaft and associated rocket cover.

The conventional method of journaling a camshaft in the engine blockpresents problems of assembly and repair which increase the cost ofmanufacturing and maintaining internal combustion engines.

It is an object of this invention to provide a rocker cover for aninternal combustion engine in which a camshaft is journaled.

Another object of this invention is to provide an internal oil passagethrough the center of the camshaft for delivering oil under pressure tometering jets in the base circle of each cam for lubricating the contactbetween the cam and its associated rocker arm and also to discharge oilin the form of an oil fog within the space between the rocker cover andthe engine block for lubricating the valve stems and tips locatedtherein.

A further object of this invention is to provide integral journals inthe rocker cover for rotatably sup-porting the camshaft therein and toprovide an oil passage in one of the journal pedestals for conveying oilunder pressure from the engine block to an annular groove formed in themating bearing surface of the camshaft such that the pressurized oil maybe fed to the internal oil passage of the camshaft through cross drilledholes in register with the annular groove.

These and other objects will be apparent as reference is made to thespecification and drawings wherein:

FIGURE 1 is a front view of an internal combustion engine utilizing thepresent invention;

FIGURE 2 is a cross-sectional view of the internal combustion engine ofFIGURE 1, with sections cut away, and illustrating the interrelation ofthe rocker cover, carnshaft, rocker arm, lash adjuster, valve andpiston;

FIGURE 3 is a view in the direction of the arrows substantially alongthe line 3-3 of FIGURE 2 showing the camshaft journaled in the rockercover;

FIGURE 4 is a view in the direction of the arrows substantially alongthe line 4--4 of FIGURE 3, illustrating the rocker cover; and

FIGURE 5 is a view in the direction of the arrows substantially alongline 5-5 of FIGURE 3 showing the interconnecting oil galleries of theengine block, oil passage of the rocker cover, annular groove of thecamshaft journal and feeder passage and internal oil passage of thecamshaft.

Referring now to the drawings, as best seen in FIG- URES 1 and 2, aninternal combustion engine indicated generally by the numeral 10includes an engine block 12, a crankshaft 14 and a camshaft 16.

A crankshaft sprocket 18 and camshaft sprocket 20 are secured to thecrankshaft and camshaft, respectively,

for rotation therewith. An auxiliary units pack-age 22 is secured to theengine block 12 and includes an auxiliary drive shaft 24 having anauxiliary drive shaft sprocket 26 secured thereto for rotationtherewith. A chain tim-- ing belt 28 operably connects the crankshaftsprocket 18, camshaft sprocket 20 and auxiliary drive shaft sprocket 26for rotating the respective associated shafts in phase during operationof the engine.

Referring now to FIGURES 2 through 5, the camshaft 16 is rotatablysupported in a rocker cover 30. The rocker cover 30 is secured to theengine block 12 by a plurality of bolts 32 with a conventional gasket 34positioned therebetween for sealing the juncture. A plurality of camlobes 36 are formed integrally at spaced intervals longitudinally alongthe camshaft 16. Each cam 36 contacts a rocker arm 38 for actuating itsassociated valve mechanism. The valve mechanism includes the rocker arm38 having a socket 40 on one end thereof fitted on the spherical head onthe upper end of a conventional hy draulic lash adjuster 42 which servesas a pivot for the rocking arm 38. The other end 44 of the rocker arm ispositioned on the tip 46 of a valve stem 48 of an engine valve 50. Acompression return spring 52 is positioned about the valve stem 48 andbiases the valve into contact with the rocker arm in a conventionalmanner.

As the camshaft 16 is rotated, each cam 36 successively pivots itsrespective rocker arm 38 about the spherical head of its associated lashadjuster 42 and overcoming the biasing action of the compression spring52 moves its respective valve 50 longitudinally, thereby opening thevalve in a normal manner. Upon further rotation, the return spring 52maintains the tip 46 in contact with the end 44 of the rocker arm 38,closes the valve '50 and maintains the rocker arm 38 in contact with cam36.

The camshaft 16 has a plurality of journals 54 integrally formed on thecamshaft and positioned to be rotatably supported in mating journalpedestals 56 integrally formed in the rocker cover 30. An aperture 58extending longitudinally in the center of camshaft 16 is threaded ateach end and effectively sealed at each end by bolts 60 and 62,respectively. Bolt 60 and associated washer 63 also secured the keyedsprocket 20 to the end of camshaft 16 in abutting relation .to therocker cover 30. At the other end bolt 62 and washer 66 secure thrustwasher 68 against rocker cover 30. A plug 70 is installed over bolt 62with a tight fit against thrust washer 68 and rocker cover 30 forsealing against admission of undesirable dirt.

The aperture 58 serves as an integral oil passage for delivering oilunder pressure to metering jets 64 extending from the aperture 58 to thesurface of the base circle of each cam lobe 36. Oil under pressure isdelivered to the internal oil passage 58 by a cross drilled hole '72which extends from the passage to the surface of the associated journal54.

An annular groove 74 is formed on the surface of journal 54 in registerwith the cross drilled hole 72. An oil passage 76 extends through thejournal pedestal 56 and connects the groove 74 to an oil gallery 78 inthe engine block 12 which carries oil under pressure for lubricating theengine and supplying oil to the camshaft.

During operation, the oil under pressure is sprayed from the meteringjets 64 to create an oil fog in the space between the rocker cover 30and the engine in block 12 and lubricates the point of contact of thecam 36 and rocker arm 38. The oilfog lubricates the valve stem for itslongitudinal movement and the contact between the rocker arm 38 andvalve tip'46.

Thus, it can be seen that by utilizing this invention a hollow camshaftmay be used as an oil passage for the distribution of oil under pressureto lubricate the contacts between the cam surface and the rocker arm andto further lubricate operating mechanism in the area between the rockercover and the engine block by means of an oil fog created by expulsionof oil through the metering jets.

By using the interior of the camshaft as an oil passage,

manufacturing costs are reduced in the construction of the rocker coverby simplifying the design so that the cover may be produced byconventional die casting means. In the die casting of the rocker cover,the journal pedestals are cast integrally with the rest of the rockercover and eliminate the need of additional nuts and bolts to securebearing surface for supporting the camshaft journals.

By securing the bolts at each end of the camshaft after the shaft hasbeen positioned in a rocker cover, the ends of the oil passage areeffectively sealed and the camshaft.

is properly positioned within the coverfor operation. Such an assemblyreduces the cost of manufacturing and simplifies the assembly operation.

While but one embodiment of this invention is shown and disclosed it isobvious that variations may be had within the scope of the followingclaims.

I claim:

1. In combination in an internal combustion engine having an engineblock,

a plurality of rocker arms,

a valve for each rocker arm movably supported in said engine block andhaving a valve tip contacting one end of the associated rocker arm foractuation thereby,

a lash adjuster for each rocker arm mounted in said engine block andcontacting the other end of the associated rocker arm,

a rocker cover removably mounted on said block and enclosing said rockerarms, said valves and said lash adjusters and a camshaft rotatablyjournaled in said rocker cover and having a plurality of cams oneengaging each of said rocker arms for actuation thereof,

whereby removal of said rocker cover from said engine block disengagessaid camshaft from engagement with said rocker arms.

2. The combination of claim 1 wherein said lash adjusters arehydraulically actuated to properly adjust the valve actuating mechanismduring engine operation, when said mechanism is enclosed by said rockercover.

3. The combination of claim 1 wherein said rocker cover comprises a diecast member sealingly secured to said engine block to define therewith arocker compartment and a plurality of journal pedestals integral withsaid die cast member, and disposed within said compartment, saidcamshaft being disposed within said compartment and having a pluralityof journals received within said journal pedestals to rotatably supportsaid camshaft.

4. The combination of claim 3 and further comprising an oil gallery insaid engine block, oil distribution means in said camshaft to supplylubricant to said rocker compartment and an oil supply passage in one ofsaid journal pedestals, said oil supply passage connecting said blockoil gallery and said camshaft oil distribution means to supply lubricantto said camshaft 'oil distribution means.

References Cited UNITED STATES PATENTS 1,469,063 9/1923 Wills 184-61,497,503 6/1924 Greuter 1846 1,612,372 12/1926 Gussman 184-6 FOREIGNPATENTS 81,212 8/ 1920 Austria.

SAMUEL ROTHBERG, Primary Examiner.

H. S. BELL, Assistant Examiner.

1. IN COMBINATION IN AN INTERNAL COMBUSTION ENGINE HAVING AN ENGINEBLOCK, A PLURALITY OF ROCKER ARMS, A VALVE FOR EACH ROCKER ARM MOVABLYSUPPORTED IN SAID ENGINE BLOCK AND HAVING A VALVE TIP CONTACTING ONE ENDOF THE ASSOCIATED ROCKER ARM FOR ACTUATION THEREBY, A LASH ADJUSTER FOREACH ROCKER ARM MOUNTED IN SAID ENGINE BLOCK AND CONTACTING THE OTHEREND OF THE ASSOCIATED ROCKER ARM, A ROCKER COVER REMOVABLY MOUNTED ONSAID BLOCK AND ENCLOSING SAID ROCKER ARMS, SAID VALVES AND SAID LASHADJUSTERS AND A CAMSHAFT ROTATABLY JOURNALED IN SAID ROCKER COVER ANDHAVING A PLURALITY OF CAMS ONE ENGAGING EACH OF SAID ROCKER ARMS FORACTUATION THEREOF, WHEREBY REMOVAL OF SAID ROCKER COVER FROM SAID ENGINEBLOCK DISENGAGES SAID CAMSHAFT FROM ENGAGEMENT WITH SAID ROCKER ARMS.